Georgia weather: Wide swings from bitter to balmy

The winter climate outlook for Georgia is, in a word, variable. Georgians this winter can expect wide swings in temperatures with several extremely cold outbreaks. The best advice is to prepare for very cold weather.

There will also be times when temperatures will be much above normal, reminding us why we like living in the South.

With wide temperature swings expected, the probability of severe thunderstorms and tornados throughout the winter is above normal, too.

Winter tornados are common in Georgia. They can happen any time of the day or night. A NOAA weather radio is an essential safety item that all homes, businesses, churches and places where people gather should have.

In the mountains, low temperatures below zero can be expected this winter. Single digit lows can be expected as far south as the northern Coastal Plain. Much of south Georgia can expect lows around 10 degrees. Even along the coast, lows in the lower teens are expected this winter.

However, the winter also promises periods of very nice weather. High temperatures ranging from the upper 60s in the mountains to around 80 in south Georgia are expected. Atmospheric scientists have a good understanding of the general climate pattern for the winter. What we don't have is a good ability to forecast the timing of major cold outbreaks and warm periods weeks in advance.

Accurate forecasts of specific daily temperatures are only available for six to 10 days in advance. The winter climate pattern in the Southeast is primarily determined by the Southern Oscillation — El Nino, or ENSO, phase. In the El Nino phase, Georgia expects a cool, wet winter. In the La Nina phase, we expect a warm, dry winter. Now, though, we're in a neutral phase. For Georgia, a neutral phase brings wide swings in temperature.

All major cold outbreaks that have affected Florida citrus have occurred during neutral phase winters.

> The rainfall outlook is uncertain. Under the neutral phase, winter rainfall patterns show great variability, and atmospheric scientists have very little skill in forecasting it. Some neutral-phase winters are very dry, while others are very wet. Most are near normal.

With periods of extreme cold, there's a better chance than normal that Georgia will have some frozen precipitation this winter. At least one major winter weather event is expected across north Georgia this winter.

Real-time weather conditions from the University of Georgia network of weather stations are available at www.georgiaweather.net.

(David Emory Stooksbury is the state climatologist and a professor of engineering and atmospheric sciences in the University of Georgia College of Agricultural and Environmental Sciences.)